The operation and management of subterraneon wells which produce hydrocarbon gas require the volume of the produced gas to be determined. This is true for gas obtained from gas wells and also for gas separated from fluid produced by oil wells. A common method of determining the volume is to take readings of the static and differential pressure of the gas as it flows through a separate meter line. Changes in pressure cause movement of recording arms on which marking pens are mounted. The pens are in contact with a circular chart rotating about a central axis so that a continuous record is obtained of these pressures over a set period of time. When the chart has completed a full rotation, a new chart replaces it in order to keep a continuous record of the gas pressures.
These gas charts must be read or integrated to convert the pressure readings to flow volume. Typically, they are sent to specialists who perform this task. In addition to the cost of the integration, the cost of paper and pens contribute to an overall cost that is quite substantial. Moreover, storage of the charts requires a large amount of space, particularly for installations in which many wells are operated. An added problem is the tendency of the ink on the paper charts to run when exposed to moisture, which can adversely affect their accuracy and integration. Still another problem involves excessive delays sometimes encountered between a chart change and the determination of gas volumes from the data on the chart.
Although it would be highly desirable to be able to overcome these problems, it is not practical to develop an entirely new system of measuring gas flow in view of the great cost of replacing all the existing meters with the hardware of such a new system. It would be far preferable to be able to improve or modify existing installations and methods in order to reduce the costs and problems referred to above.